add installation for task1

Author: lumixraku

Notes15.md

@@ -37,12 +37,21 @@ Radiance 其实是在 Irradiance 基础上增加了方向
 或者说 Irradiance 是四面八方的 Radiance 的积分
 
 ## BRDF 双向反射分布函数
-通俗的说,  有多少能量, 从某个方向进来, 到反射方向上会分布多少能量.
+通俗的说, BRDF是在解决光从某个方向打到以个物体上, 光向不同方向去反射的能量分布.
+
+描述了光线和物体如何相互作用
 
 对于反射的理解:
 
 Whitted Style 光线打到某一个物体上, 然后被弹走了(方向改变了).
 
 另一种理解: 光线打到某一个表面, 结果被吸收了, 然后又朝特定的方向发射出去了.
 
-如何把某一个方向收集到的能量反射到其他方向上去?  BRDF 定义了如何去分配这些能量.
+ωi 表示不同方向的入射光
+
+![image](https://github.com/lumixraku/NotesForGraphics/raw/master/images/brdf.png)
+
+
+射出的radiance 可能成为其他点的入射radiance (此刻被照亮的物体本身作为光源存在了)
+
+![image](https://github.com/lumixraku/NotesForGraphics/raw/master/images/brdf2.png)

README.md

@@ -1 +1,63 @@
 # NotesForGraphics
+
+
+## Prepare
+
+```
+brew install eigen
+
+brew install opencv@2
+
+brew tap brewsci/science
+
+brew install pkg-config
+
+export PKG_CONFIG_PATH=/usr/local/lib/pkgconfig/
+
+ln -s /usr/local/Cellar/opencv@2/2.4.13.7_7/lib/pkgconfig/opencv.pc $PKG_CONFIG_PATH
+```
+
+After everything have done , when you run this command  `pkg-config --cflags --libs opencv`  will see this:
+```
+-I/usr/local/Cellar/opencv@2/2.4.13.7_7/include/opencv -I/usr/local/Cellar/opencv@2/2.4.13.7_7/include -L/usr/local/Cellar/opencv@2/2.4.13.7_7/lib -lopencv_calib3d -lopencv_contrib -lopencv_core -lopencv_features2d -lopencv_flann -lopencv_gpu -lopencv_highgui -lopencv_imgproc -lopencv_legacy -lopencv_ml -lopencv_nonfree -lopencv_objdetect -lopencv_ocl -lopencv_photo -lopencv_stitching -lopencv_superres -lopencv_ts -lopencv_video -lopencv_videostab
+```
+
+I'm using Xcode as my C++ IDE, create a command line Project for Task1.
+
+Add this to your project.
+
+Add following to Header Search Paths (Eigen requires first dependency.)
+```
+/usr/local/include
+/usr/local/Cellar/opencv@2/2.4.13.7_7/include
+```
+And make it no-recursive. (Though medium blog says this should set recursive, I found if set recursive would cause fatal error when building)
+
+Then add this to library search path.
+```
+/usr/local/Cellar/opencv@2/2.4.13.7_7/lib
+```
+
+Add `pkg-config --cflags --libs opencv` output to Other Linker Flags
+```
+-I/usr/local/Cellar/opencv@2/2.4.13.7_7/include/opencv -I/usr/local/Cellar/opencv@2/2.4.13.7_7/include -L/usr/local/Cellar/opencv@2/2.4.13.7_7/lib -lopencv_calib3d -lopencv_contrib -lopencv_core -lopencv_features2d -lopencv_flann -lopencv_gpu -lopencv_highgui -lopencv_imgproc -lopencv_legacy -lopencv_ml -lopencv_nonfree -lopencv_objdetect -lopencv_ocl -lopencv_photo -lopencv_stitching -lopencv_superres -lopencv_ts -lopencv_video -lopencv_videostab
+
+```
+
+## TroubleShotting
+
+### install opecv2
+https://www.learnopencv.com/install-opencv3-on-macos/
+
+https://medium.com/beesightsoft/macos-mojave-10-14-3-setup-environment-for-opencv4-0-1-c-develop-fcae955d6b33
+
+
+### install eigen for mac
+https://stackoverflow.com/questions/35658420/installing-eigen-on-mac-os-x-for-xcode
+
+### Undefined symbols for architecture x86_64: error
+https://stackoverflow.com/questions/24985713/opencv-undefined-symbols-for-architecture-x86-64-error
+
+
+### xcode No member named 'FILE' in the global namespace
+https://stackoverflow.com/questions/30638320/xcode-cstdlib-no-member-named-xxx-in-the-global-namespace

images/Google Chrome_2020-04-13 [email protected]

@@ -0,0 +1,6 @@
+
+## eigen
+https://stackoverflow.com/questions/35658420/installing-eigen-on-mac-os-x-for-xcode
+
+## opencv
+https://stackoverflow.com/questions/13953570/opencv2-opencv-hpp-file-not-found